Identifying bacteria and studying bacterial diversity using the 16S ribosomal RNA gene-based sequencing techniques: A review

The cytotoxicity of Pyrus pyraster and Pyrus spinosa leaf and bark extracts, as well as their major compound, arbutin was tested against melanoma cell line (Fem-x) and healthy human embryonic lung fibroblast (MRC-5). The methanol extracts of P. pyraster (leaves and bark) exhibited significant cytotoxic effects towards Fem-x cells, with IC50 ranging from 11.55 to 46.78 μg/ml, and the corresponding dichlormethane extract IC50 ranging from 21.59 to 13.34 μg/ml. The dichlormethane extract of P. spinosa bark was active against both cells lines tested (IC50 11.97 and 12.92 μg/ml). Arbutin was found to be no cytotoxic against both Fem-x and MRC-5 cells in vitro with an IC50 > 200 μg/ml. Tested extracts have shown moderate and no cytotoxicity against healthy MRC-5 cell line. The wild pear’s extracts and arbutin showed antibacterial activity against all bacteria species. Minimal inhibitory concentration (MIC) ranged between 0.1-0.3 mg/ml, while minimal bactericidal concentration (MBC) was 0.2-0.3 mg/ml. All extracts and arbutin showed antifungal activities in the MIC range of 0.05-0.2 mg/ml and MFC range of 0.1-0.3 mg/ml. Key words: Pyrus pyraster, Pyrus spinosa, arbutin, antimicrobial activity, cytotoxicity.